A duke joins the crew of an all-female traveling circus to woo its star boxer in Spencer’s Regency-set The Boxing Baroness (Kensington, Nov.).

What inspired your boxing heroine?

I kept running across records of the Boxing Baroness when I was researching other books and every time I read something about this woman, it was slightly different. The first thing I read was that her name was Katherine and she was married to the Earl of Barrymore. Then I read that her name was really Mary Anne Pearce and that she was the earl’s mistress. There are a couple of cartoon illustrations that depict the Boxing Baroness, but none of those seemed to have the story straight either. Nobody really knows who she was, which goes to show that if you weren’t a diarist at the time, you didn’t leave much of a mark, especially if you weren’t wealthy. I ended up contacting a librarian from the Library of Congress who gave me everything she had on the subject, but even that wasn’t much. So then I started looking to see what kind of role women had in any type of typically masculine pursuits. The whole series is based on what traces I found of women doing sorts of masculine activities. The next book is called The Dueling Duchess—and there are actual accounts of women having duels!

Marianne makes an admirable heroine who, despite her lower status, can hold her own in conversation with the duke. How did you develop her character?

Marianne was raised to be a lady and went to an expensive private school, but her expectations were one thing while her reality is another. After she had a love affair with a very unsavory aristocratic man, her thoughts would have been, “Well, I may as well do what I want now because I am going to be an outcast no matter what.” Back then, you would have been stigmatized by your association with a circus. When you look at what jobs women could have, they were companion, governess, teacher, or prostitute. So I tried to imagine what I would feel in her situation, given the conventions of the time. I think it is really important when writing historical romance—though the characters have perfect teeth and are really handsome—to keep the gender conventions as close to the truth as possible because it makes what women did achieve all the more admirable.

Tell me about the hero, St. John “Sin” Powell, Duke of Staunton.

This is the first time I’ve written about a duke, which is kind of a big deal in historical romance. I tend to gravitate toward societal outcasts, but instead Sin is a very proper character. I love class difference and always find that it comes with built-in conflict. So I thought I’ll give Marianne the stuffiest, starchiest man in Britain to deal with. But he also has his softer side and is intrigued by this woman who does not fit the mold.